The notes and correspondence contained in this series comprise a variety of topics. Subseries 1 contains Carnap's notes on and correspondence with individuals generally involved in research and study of probability. They are listed alphabetically by last name. Subseries 2 includes Carnap's notes on mathematics and correspondence with publishers. UCLA administrative documents are comprised under subseries 3. Finally, subseries 4 features Carnap lecture notes, some of them dating back to his time in Prague and Chicago.